1. Field of the Invention
The present invention relates to a collapsible platform assembly for an extension ladder and more particularly to a collapsible platform assembly rotatably secured near the top of an extension ladder having a platform for supporting a person, having a storage or retracted position in which the platform is generally co-planar with the ladder which allows it to be easily stored and transported as an extension ladder and an extended position in which the platform can be extended and directly supported by the roof, which define grab rails that extend beyond the height of the roof and allow a user to walk through the top of the ladder when the collapsible platform assembly is in an extended position and optionally includes a pair of retractable handrails for added safety for use when the user is on the platform.
2. Description of the Prior Art
Various devices are known in the art for attachment onto an extension ladder. For example, U.S. Pat. Nos. 309,435; 404,511; 434,462; 1,645,879; 2,035,537; 2,592,006; 3,963,095; 6,394,229; 6,513,625; and 6,533,069 as well as U.S. patent application No. U.S. 2007/0267251 A1. British patents GB 2 261 906 and GB 2 387 868 also disclose devices for attachment to extension ladders for various purposes.
U.S. Pat. Nos. 1,645,879; 2,592,006; 6,394,229 as well as U.S. patent application publication No. U.S. 2007/0267251 A1 and British Patent No. GB 2 387 868 all disclose devices for attachment to an extension ladder which are used to prevent the ladder from being supported by a gutter or roof edge. U.S. Pat. Nos. 6,513,625 and 6,533,069 also disclose devices for securing a ladder with respect to a roof or other structure.
U.S. Pat. No. 309,405 relates to a removable platform that can be removably attached to spaced apart rungs of the ladder and spaced away from the point of support of the ladder with respect to the roof. The platform for supporting a paint can or tools while a workman is on the ladder. The configuration of the device makes it unsuitable to act as a support point to support the ladder with respect to a roof or structure.
U.S. Pat. No. 404,511 discloses a device configured as a supplementary ladder which is rotatably connected on one end to an extension ladder with the opposing ends including hardware for enabling the supplementary ladder to be secured to a window sill on a building and provide support for the ladder relative to the window sill. The supplementary ladder is provided with hooks which allow one end of the supplementary ladder to be rotatably and removably connected to a rung on the extension ladder.
U.S. Pat. Nos. 434, 462, and 2,035,537 all disclose collapsible platform assemblies for attachment to extension ladders. In particular, U.S. Pat. No. 434,462, similar to U.S. Pat. No. 404,511, discloses a supplementary ladder rotatably connected to one rung on an extension ladder. The other end of the extension ladder includes a platform attached to a rung of the supplementary ladder. The platform covers a portion of an extending end of the supplementary ladder and is formed with two plates hinged together. In a use position, the plates are configured to be side by side. In a storage position, the hinges allow the platform to be folded in half. The supplementary ladder is configured to be folded up and stored between the side rails of the extension ladder when the supplementary ladder is not in use. In this storage position, the rungs in the supplementary ladder act as rungs for the extension ladder. The platform when folded in half unblocks one of the rungs on the supplementary ladder when the supplementary ladder is in a storage position. A pair of pivotally mounted clamps is used to secure the supplementary ladder in a storage position. These clamps when released allow the supplementary ladder to be extended. A pair of cords secures the free end of the supplementary ladder to a position adjacent the free end of the supplementary ladder in a use position. The supplementary ladder is spaced away from the top of the extension ladder to allow a workman to paint the side of a building beneath the roof.
U.S. Pat. No. 2,035,537 discloses a collapsible platform assembly that can be attached to one end of an extension ladder. The collapsible platform assembly is attached to the side rails of an extension ladder on one end by way brackets which allow the frame and the floor of the platform to be pivotally mounted thereto. The frame and the floor are also secured by way of chains which are bolted to the free ends of the extension ladder. The extension ladder is pivotally mounted to a truck. Support for the extension ladder is provided by a support ring on the truck. Thus, the collapsible platform is not configured to provide support of the ladder relative to a building or roof.
The devices discussed above for providing platforms for an extension ladder simply provide a platform for a workman to stand. These devices are not configured to enable the platform to contact a roof and provide support nor do these devices secure the ladder relative to the roof. The other devices discussed above likewise do not secure the ladder to the roof. As such, the devices described above do not satisfy certain government regulations. In particular, regulations have been developed that require ladders to be secured at the top to a support that will not “deflect” under load For example, OSHA Regulation 29 CFR 1926.1053(b)(1) states:                “When portable ladders are used for access . . . , the ladder shall be secured at its top to rigid support that will not deflect . . . . In no case shall the extension be such that ladder deflection under a load, by itself, cause the ladder to slip off its support.”        
These regulations also require that the ladders have a “grasping device, such as a grab rail . . . to assist in mounting and dismounting the ladder.” The devices discussed above, for example, as disclosed in U.S. Pat. Nos. 434,462 and 2,035,537, disclose utilize cords and chains and thus do not include grab rails. Thus, there is a need to provide a device for enabling the top of a ladder to be secured relative to the top of a roof. There is also a need to provide a device that includes grab rails and therefore complies with the government regulations.